Telephone-transmitter.



No. 643,993. PatentedFeh. 20, I900.

c. E. TUCKERE. s. JENKINS.

TELEPHONE TRANSMITTER. (Application filed. May 23, 189E) (No Model.)

Clue/{19617. T

wihwmy UNITED STATES PATENT OF I E.

CHARLES E. TUCKER AND LOUIS S JENKINS, OF YORK, PENNSYLVANIA.

TELEPHONE-TRANSMITTER.

SPECIFICATION forming part of Letters Patent No. 643,993, dated February 20, 1900.

Application filed May 23,1899. Serial No. 717,949. (No model.) i

To aZZ whom it may concern:

Be it known that we, CHARLES E. TUCKER and LOUIS S. JENKINS, citizens of the United States, residing at York, in the county of York and State of Pennsylvania, have invented certain new and useful Improvements in Telephone-Transmitters; and we do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to telephone appliances employing a granularresistance as the means for producing undulations and variations in the current responsive to the soundwaves striking the initial diaphragm.

The invention is peculiarly adapted for tele phone-transmitters, as it enables the granular resistance material being hermetically sealed and protected from the baneful influences of moisture and climatic changes.

It is a well-known fact that all transmitters heretofore constructed and depending upon the front cap or cover as the means of forming electrical connection with the vibrating electrode and to secure the same in its proper position are liable to be thrown out of adj ustment when in the hands of inexperienced persons, as the removal of the cap or cover, upon which is mounted the mouthpiece, practically disassembles the instrument. The removal of the cap or cover is very often necessary in order to clean it upon the inside, as the condensation of the human breath will cause the connection to corrode and very often become offensive. To remedy this it has heretofore been necessary for telephone-exchanges to employ an experiencedperson for this work, which is an item of considerable expense.- Another source of considerable annoyance in telephone-transmitters of the granular type is the packing of the granulated carbon or equivalent material. This has been found to be due to several causes, one of which is inaccurate construction. Another is the using of materials that conflict with each other when expanding and contracting by a change of temperature or other conditions. The result of this is the electrodes are thrown out of adjustment and the granules become corroded and dampened and the instrument becomes commercially useless within a short space of time. This is especially true with transmitters that have a case or housing for the back electrode composed of hard rubber, wood, fiberoid, or other insulating material and a metallic cap or cover. They maybe originally hermetically sealed, but the expansion and contraction being so radically difierent will tend to break the seal of the case and permit moisture to enter and ultimately destroy its efficiency.

This invention enables the fixed electrode and the variable-resistance material to be sealed, thereby obviating expensive and frequent repairs. Another vital feature of importance is the direct interposition of the granular resistance material between the fixed and the vibratory electrodes, the latter being dampened thereby and serving to hold the granules in the cell or chamber of the fixed electrode, thereby simplifying the construction and attaining beneficial results.

:For a full understanding of the merits, advantages, and' details of construction of the invention reference is to be had to the following description and drawings hereto attached.

As previously intimated, the invention can be applied to telephone apparatus of various typesandmakes. Henceitistobeunderstood that changes in the form, proportion, and minor details of construction may be'resorted to without departing from the spirit or sacrificing any'of the advantages thereof.

In the drawings forming a part of this specification, Figure 1 is a central longitudinal section of a telephone-transmitter, showing the application of the invention. Fig. 2 is a perspective view of the housing or frame supporting the electrodes, the clamp-ring, fixed electrode, and clamp-screw.

The same parts in each of the views are referred to in the description and indicated by like reference characters.

The housing or frame 1 to which the electrodes are attached and which receives the granular resistance material is of circular outline, the central portion being depressed, forming a chamber 2, and the peripheral portion having a rim 3, formed with an annular shoulder vat, constituting a seat for the diaphragm or vibratory electrode 5, the portion ICO of the rim beyond the shoulder 4 being interiorly threaded to receive the clamp-ring 6, between which and the shoulder 4 the electrode 5 is secured. The inner end of the chambered part 2 has an opening 7, through which the clamp-screw or bolt 8 passes, said opening being sufficiently large to prevent contact of the screw 8 with any portion of the frame.

The fixed electrode 9 is a block of carbon secured to the frame Within the chamber 2 and is provided in its face with a cell, pocket, or chamber 10, in which the granular material 11 is placed. This cell or chamber may be of any shape and is preferably of hemispheroidal form, so as to cause the granules to maintain close contact and prevent packing, which would occur if the chamber were of angular formation. The edge portion of the electrode, exterior to the chamber 10, is beveled rearwardly or away from the electrode 5, thereby lessening the chances for interference or short-circuiting of the current. A small space exists between the opposing portions of the electrodes 5 and 9, and to guard against possible contact between them an insulation 12 is provided and attached to the electrode 9. This insulation is of such a character as not to dampen the diaphragm should it perchance come in contact therewith and is normally spaced therefrom, paper, vulcanite, or like dense material being employed. The edge produced by the intersection of the outwardly-flaring walls of the chamber with the receding marginal portion of the electrode 9 approaches as close to the inner surface of the vibratory diaphragm as it is possible to adjust it without affecting a contact between the electrodes when the instru ment is in service. The space is less than the diametrical extent of the granules 11. Hence the latter cannot escape, and should a particle come between the said edge and vibratory diaphragm or electrode it will readily escape by reason of the outwardly-flaring character of the space formed between the opposing surfaces or portions of the electrodes. The electrode may have any desired number of chambers or cells within the purview of the invention, and it is not essential that the fixed electrode be the chambered one, although preferable, as it is contemplated within the scope of the invention to apply a chambered electrode to the vibratory electrode.

The granular resistance material 11 is illterposed between the two electrodes and is placed within the chamber 10 and is of larger diametrical extent than the space formed between said electrodes to prevent their escape or wedgin g between them. The granules bear against the vibratory electrode or diaphragm and dampen it without appreciably interfering with its amplitude of vibration, yet perfectly responsive thereto, so as to produce the undulation of current essential to the transmission of sound-waves. The formation of the chamber or cell 10 is such as to cause all the granules to move in unison with the vibration of the diaphragm.

Insulating material 13 is interposed between the electrode 9 and the inner side of the frame, and other insulating material 14 is placed exterior to the frame and confined between it and the nut 15, placed upon the threaded end of the screw 8. A nut 16 is mounted upon the screw 8, and the lead-wire 17 is clamped between the two nuts and 16.

The diaphragm or vibratory electrode 5 may be of any material generally used for this purpose, but is a carbon disk and is seated upon the shoulder t and clamped thereon by the metallic ring 6, the latter being noted at 18, to receive the ends of a spanner, by means of which the ring is tightened or loosened.

The frame 1,with its operating elements, is located in the case 19, shouldered at 20 to form a seat therefor, and the cap 21 is screwed to the case 19 and clamps the frame between it and the shoulder 20, said cap-plate carrying the usual mouthpiece 22. The lead-Wire 25 is attached to the case at'any convenient point.

Having thus described the invention, what is claimed as new is- 1. In telephone apparatus, opposing electrodes, one of the electrodes having a chamber, a dense or non-dampening insulating material interposed between the opposing faces of the electrodes and attached to one of the said faces and spaced from the other face, and a granular resistance material in the chamber held in place by direct contact with the opposite electrode, substantially as specified.

2. In telephone apparatus, a vibratory electrode, a fixed electrode having a central chamber formed with outwardly-flaring walls and having the marginal portion receding and spaced from the vibratory electrode, said receding marginal portion intersecting with the walls of the chamber and forming a projectin g edge portion which approaches very close to the vibratory electrode without contact therewith, a non-dampening insulating material applied to the receding marginal portion of the fixed electrode, a granular resistance material placed in the outwardly-flaring chamber and held therein by direct contact with the vibratory electrode, substantially as set forth.

3. In a telephone-transmitter, a casing open at one side, a frame composed of independent sections, inclosing the fixed and vibratory electrodes and removably fitted in the casing through its open side and seated upon the portion near the open end thereof, and a cap-plate provided with the mouthpiece and having screw-thread connection with the casing said frame being clamped by the casing and cap-plate, substantially as set forth.

4. The herein-described telephone-transmitter consisting of a chambered. frame of piece and clamping the frame between it and metal, a fixed electrode secured within the the case, substantially as described. frame and insulated therefrom and having a In testimony whereof we affix our signachamber, a vibratory electrode closing the tures in presence of two witnesses.

5 open side of the frame and clamped against a shouldered part thereof, granular material placed in the chamber of the fixed electrode and held in place by direct contact with the Witnesses: vibratory electrode, a case receiving the SAMUEL F. SHAFFER, [0 frame, and a cap-plate bearing the mouth- WILLIAM G. HESS. 

